1. Field of the Invention
The present invention relates to a lens barrel enabled to adjust the position of an optical axis of a frame member and/or the inclination of the optical axis thereof.
2. Description of the Related Art
A conventional lens adjusting device for correcting misalignment of the center of an optical axis of a lens according to a utility model, which relates to a lens frame and is proposed in the Japanese Utility Model Laid-Open No. 60-150511 Official Gazette, utilizes rotatable eccentric screws or pins. This conventional device has an adjusting structure including plural notch portions, each of which is provided in an outer periphery of the lens and engaged with an eccentric pin. The aforementioned device causes a micro-movement of the lens in a direction perpendicular to the optical axis thereof by rotating the eccentric pins, so that the centering of the lens is achieved.
However, the conventional device proposed in the Japanese Utility Model Laid-Open No. 60-150511 Official Gazette requires plural eccentric pins and is thus disadvantageous in cost thereof. Further, it is necessary for moving the lens in the direction perpendicular to the optical axis to simultaneously or alternately rotate plural eccentric pins. Therefore, the conventional device has a drawback in that it is difficult to perform the centering of the lens. Moreover, in the case of some support structure for the lens, there is the possibility that when the eccentric pins are rotated, the optical axis of the lens does not simply perform translation but inclines.
Furthermore, a conventional method of assembling a lens system for correcting the misalignment of the lens frame, which includes the inclination of the optical axis thereof, according to an invention is proposed in the Japanese Patent Laid-Open No. 59-68710 Official Gazette. According to this conventional method, a lens system is assembled and aligned by correcting the misalignment including the inclination of the optical axis of the lens in a state in adjacent lenses are held by space forming rings, and by subsequently bonding the lenses with the space forming rings on the outer periphery thereof and fixing the lenses thereon.
In the case of the assembling method proposed in the Japanese Patent Laid-Open No. 59-68710, there is the probability that the optical center is changed simultaneously with adjusting the inclination of the optical axis of the lens. Hence, the adjustment of only the inclination of the optical axis of the lens cannot be performed. Further, even in the case of adjusting the inclination and position of the optical axis of a lens, both the inclination and position thereof simultaneously change, as described above. Thus, this conventional method has a drawback in that it is difficult to perform such an adjusting operation.
Moreover, a semiconductor laser light source serving as a device including an optical axis position adjusting structure of a support portion (namely, a frame portion) for supporting an optical component is disclosed in the Japanese Patent Publication No. 61-46895 Official Gazette, and has an optical axis position adjusting structure that can perform fine adjustment of the optical axis position of a frame portion for supporting a semiconductor laser chip. FIG. 40 is an enlarged diagram illustrating the concept of the optical axis position adjusting structure.
In the optical axis position adjusting structure, a frame portion 311b for holding a laser light source portion acting as an optical component is supported against a support portion 311a through an elastically deformable cantilever-like plate spring portion 311c. When a side of a lens frame portion 311b is pushed by exerting a pressing force F.sub.0 thereon so as to adjust the optical axis position in the lateral direction of the optical component, the optical axis position Z.sub.0 is displaced leftwardly, as viewed in this figure, to a position Z.sub.1, to which the optical axis position is adjusted, by a movement amount .delta..sub.x0.
However, simultaneously, the optical axis position is displaced upwardly or downwardly by a movement amount .delta..sub.y0, so that the adjustment of the optical axis position in the upward or downward is necessary. Furthermore, when the center of the optical axis is moved from the position Z.sub.0 to the position Z.sub.1, the optical component rotates around the optical axis. This adversely affects the entire optical system. Thus, this conventional device has a drawback in that the adjustment of the optical axis position cannot be favorably achieved.